The method and apparatus of the invention is appropriate for the separation of biological fluids comprising an aqueous component and are one or more cellular components. For example, potential uses of the invention include extracting, from a volume of whole blood, a plasma component and, a first cellular component including platelets. The first cellular component alternatively may be a buffy coat component. The invention is also useful when the pooling of buffy coat or random donor platelet collections occurs for a platelet product.
European patent application EP 1566191 describes a method and an apparatus for separating a volume of whole blood into at least two components in accordance with various separation protocols. For example, one protocol provides for the separation of a volume of whole blood into a plasma component, a platelet component, and a red blood cell component. The apparatus comprises a centrifuge adapted to cooperate with various bag sets, in particular a bag set comprising an annular separation bag for whole blood, which is connected to a platelet component bag, a plasma component bag, and a red blood cell component bag. The centrifuge includes a rotor for spinning the separation bag and centrifuging the whole blood contained therein, the rotor having a turntable for supporting the separation bag and a central compartment for containing the component bags connected to the separation bag; and a squeezing system for squeezing the separation bag and causing the transfer of the plasma component from the separation bag into the plasma component bag, and of the platelet component into the platelet component bag. When such a platelet product is collected it is frequently desirable to know or predict the yield of the collected product. This can be important for subsequent use of the platelet product for transfusion and when such platelet product is pooled with other collections to form a random donor platelet product.
U.S. patent application Ser. No. 11/954388 filed Dec. 12, 2007 further describes a alternate method of separating at least two discrete volumes of a composite liquid into at least two components.
Buffy coat produced from a whole blood donation is a combination of platelets and white blood cells with a small amount of red blood cells and plasma. The majority of platelets collected during a whole blood donation are in the buffy coat layer. WO 2004/018021 describes a process of separating buffy coats as well as platelets from a composite blood product. To produce a platelet dosage amount, buffy coats are pooled from many donations and re-spun in a centrifuge to separate the platelets from the rest of the buffy coat.
These pooled buffy coat platelets form the dosage of platelet product. One pooled platelet product can include buffy coat platelets from a number of collections. It is desirable that this pooled platelet product also form a consistent dose. U.S. Pat. No. 6,348,031 discloses an apparatus for pooling buffy coats to achieve a platelet dosage product.
It is against this background of the desire for a consistent and pure platelet dose product that the instant invention was conceived and developed.